Golden Bear and Olympic champion swimmer Dana Vollmer knows a lot about winning — and losing, and getting back in the pool to try again.

So when she took the Winter Commencement stage at Haas Pavilion Sunday and faced a crowd of some 500 about-to-be-new-graduates — and their beaming friends and families — she had a lot to tell them about how to face their futures:

“I challenge you to tackle the unknown, be open to learn from everything and everyone, and whatever you do, stay positive!” Vollmer told them, conjuring up examples from her own life. “Your dream life is out there; you just have to be brave enough to create it.”

Vollmer, who led the Golden Bears to their first NCAA team championship in 2009, was a four-time Olympic gold medalist before having a baby, Arlen, last year. Then, she came back and won another three medals in last summer’s Olympics in Rio.

Her keynote commencement speech followed remarks by Chancellor Nicholas Dirks, who told graduates that their rigorous education at Berkeley will serve them well as they head out into their futures.

“(It) will serve as perfect preparation for what lies ahead, for the world you are about to enter is in a state of agitated turmoil and transition,” Dirks said. “While many are understandably upset and unsettled, this is not a time to retreat from the public square….from debate…..from advocacy….from efforts on behalf of the greater good.”